Hydraulic unit for anti-slip regulated braking systems

ABSTRACT

The present invention relates to a hydraulic unit whose inlet valves are arranged in valve accommodating bores ( 2 C,  2 D) of a first valve row (X) which is spatially separated by means of a pump accommodating bore ( 5 ) from a second valve row (Y) accommodating the outlet valves, wherein several valve accommodating bores ( 2 E,  2 F) of a third valve row (Z) remote from the pump accommodating bore ( 5 ) open directly between the second valve row (Y) and the braking pressure generator ports (B 1 , B 2 ) into a first housing surface (A 1 ) of the accommodating member ( 4 ), and wherein an electric change-over valve closed in its basic position is provided in at least one valve accommodating bore ( 2 E) of the third valve row (Z) for the hydraulic communication between at least one braking pressure generator port (B 1  or B 2 ) and a suction-side connection of the pump accommodating bore ( 2 ), the hydraulic communication between said change-over valve and the pump accommodating bore ( 5 ) being established by way of a portion of a suction channel ( 6 ), the length thereof being determined by the distance between the pump accommodating bore ( 5 ) and the third valve row (Z).

[0001] The present invention relates to a hydraulic unit forslip-controlled brake systems according to the preamble of patent claim1.

[0002] German patent application DE 198 05 843 A1 discloses a hydraulicunit for a slip-controlled brake system comprising a block-shapedaccommodating member which has eight valve accommodating bores in total,arranged side by side in a first and a second valve row, withelectromagnetically operable inlet and outlet valves inserted in saidbores. Outside the two valve rows are a pump accommodating bore and twoparallel accumulator accommodating bores. The accumulator accommodatingbores are arranged paraxially relative to the valve accommodating boresand laterally to the two valve rows, while the pump accommodating boreextends in parallel to the two valve rows. Disposed centrically betweenthe two accumulator accommodating bores is a motor accommodating borethat extends paraxially relative to the accumulator accommodating boresinto the pump accommodating bore. Further, there is provision of a thirdvalve row which opens into the housing surface of the accommodatingmember at the other end thereof, remote from the braking pressuregenerator ports and the first and second valve rows. The third valverow, which is thus arranged directly adjacent to the two accumulatoraccommodating bores, ensures a simple functional extension of thehydraulic unit configured for anti-lock pressure control for the purposeof traction slip control or driving dynamics control. To this end,magnetic valves designed as electric change-over valves and closed intheir initial position are inserted into the two external valveaccommodating bores. Separating valves open in their initial positionare inserted in the form of magnetic valves into the two intermediatevalve accommodating bores of the third valve row.

[0003] The large distance between the braking pressure generator portsand the electric change-over valves, however, is disadvantageous becausecorrespondingly long suction channels from the braking pressuregenerator via the electric change-over valves to the pump accommodatingbore are necessary for the purpose of pressure fluid supply to the pumpby way of the change-over valves. Inevitably, it is also complicated toevacuate the suction channels and to fill them with brake fluid, whichis due to the high volume take-up. In addition, a correspondingly highhydraulic resistance is probable during pump operation. The necessarylong suction channels can only be made by complicated drillingoperations under aspects of manufacture.

[0004] In view of the above, an object of the present invention involvesimproving a hydraulic unit of the indicated type in such a way that theabove-mentioned drawbacks are overcome.

[0005] According to the present invention, this object is achieved for ahydraulic unit of the type mentioned hereinabove by the characterizingfeatures of patent claim 1.

[0006] Further features, advantages, and possible applications of thepresent invention can be taken from the following description of severalembodiments by way of the accompanying drawings.

[0007] In the drawings,

[0008]FIG. 1 is a three-dimensional illustration of a total view of thesubject manner of the invention for exhibiting all accommodating boresand pressure fluid channels.

[0009]FIG. 2 is a detail view of FIG. 1 for explaining the featuresessential for the invention.

[0010]FIG. 3 is a variation of the subject matter of FIG. 2 in the areaof the suction channel.

[0011]FIG. 4 is another embodiment for configuring the suction conduitbetween the braking pressure generator port and the pump accommodatingbore in the accommodating member of the hydraulic unit.

[0012]FIG. 1 shows a space diagram of all pressure fluid channels,accommodating bores for valves, pump, and accumulator within theaccommodating member 4. Electromagnetically operable inlet and outletvalves are inserted into several valve accommodating bores 2A, 2B, 2C,2D of a first and second valve row X, Y, said valves extending from thedirection of a first housing surface A1 of the accommodating member 4vertically into the valve accommodating bores 2A, 2B, 2C, 2D. The firsthousing surface A1 is arranged at right angles relative to a secondhousing surface A2, opening into which are two braking pressuregenerator ports B1, B2 in the vicinity of the outside edges of theaccommodating member 4, and this is due to the brake circuit having atwo-circuit design. Between the two valve rows X, Y the accommodatingmember 4 incorporates a pump accommodating bore 5 that extends throughthe accommodating member 4 transversely to the direction the valveaccommodating bores 2A, 2B, 2C, 2D open thereinto. On the third housingsurface A3 disposed remote from the valve accommodating bores 2A, 2B,2C, 2D, the accommodating member 4 includes a motor accommodating bore14 which points vertically into the pump accommodating bore 5 at a pointhalf the length of said pump accommodating bore 5. Further, anaccumulator accommodating bore 1 is disposed between the first andsecond valve row X, Y on either side of the motor accommodating bore 14,said bore 1 being directed into the first housing surface A1 paraxiallyto the valve accommodating bores 2A, 2B, 2C, 2D. Several valveaccommodating bores 2E, 2F of a third valve row Z open remote from thepump accommodating bore 5 vertically into the first housing surface A1of the accommodating member 4 directly between the second valve row Yand the braking pressure generator ports B1, B2. The third valve row Zincludes both electromagnetically operable separating valves open intheir basic position and electric change-over valves closed in theirbasic position. The chosen arrangement of the third valve row Z thatincludes the electromagnetic change-over valve permits an extremelyshort hydraulic connection between one braking pressure generator portB1 or B2, respectively, and a suction-side connection of the pumpaccommodating bore 5. To this end the suction conduit to the pump isbasically determined by the distance between the centers of the pumpaccommodating bore 5 and the third valve row Z. This is advantageousbecause due to the short distances and dimensions between the brakingpressure generator port B1 or B2 to the valve accommodating bore 2Ehousing the electric change-over valve, there is achieved a shortsuction channel 6 that directly opens into the pump accommodating bore 5for the pressure fluid supply of the pump in the pump accommodating bore5, said suction channel permitting low-cost manufacture andlow-resistance fluid passage. The pressure-side outlet of the pumpaccommodating bore 5 opens into a noise damping chamber 10 that isarranged remote from the second and third valve row Y, Z vertically tothe vertical plane of the first valve row X in the accommodating member4.

[0013] It becomes apparent from the space diagram showing the hydraulicunit of the invention that a pressure fluid channel system is created bymeans of straight and cross bores between the individual valve rows X,Y, Z. Said channel system provides pressure fluid ports between theindividual valve, pump and accumulator accommodating bores in conformitywith the demands of performance, on the one hand, and can be realized assimply as possibly under manufacturing technique aspects, on the otherhand.

[0014] The arrangement of the necessary pressure fluid channels in theaccommodating member 4 for one of the two brake circuits will beexplained in the following, namely between the braking pressuregenerator port B2 and the wheel brake port R2 that opens into the narrowhousing surface A2 in parallel to the braking pressure generator portB1. The braking pressure generator port B2 in the lower housing plane ofreference E1 leads into the valve accommodating bore 2E provided for anelectric change-over valve and extending from a first supply channel 9Ain the bottom housing plane of reference E1 in the direction of thevalve accommodating bore 2F arranged beside the valve accommodating bore2E and accommodating a separating valve. A second supply channel portion9B designed as an angular channel extends from the valve accommodatingbore 2F and is continued via the separating valve that is open in itsinitial position, transversely to the top into the top housing plane ofreference E2 in the direction of the noise damping chamber 10A. Thesecond supply channel portion 9B consequently crosses the pumpaccommodating bore 5 in the direction of the first valve row X providedwith several inlet valves. Shortly before the noise damping chamber 10A,a supply branch line 7 of the second supply channel portion 9B leads tothe two valve accommodating bores 2C, 2D through which fluid flows inthe direction of the housing plane of reference E1. From the valveaccommodating bores 2C, 2D, each one pressure fluid connection continuesas a wheel supply channel 8A, 8B in the bottom housing plane ofreference E1 in the direction of the second valve row Y thataccommodates the outlet valves being closed in their initial position.Thus, the wheel supply channels 8A, 8B cross below the pumpaccommodating bore 5 and are aligned in parallel to the second supplychannel portion 9B up to the valve accommodating bores 2A, 2B of thesecond valve row Y. From there, e.g. the wheel supply channel 8B as anangular channel (that means as a channel bent at right angles) continuesin the direction of the housing plane E2 to the wheel brake connectionR2. The wheel supply channel 8A extends in a vertically downwarddirection to another wheel brake connection that is arranged on thebottom side of the accommodating member 4 and is essentially covered bythe valve accommodating bore 2E. Therefore, the wheel supply channel 8A,after having crossed the first supply channel portion 9A, is deflectedin a downward direction, while the wheel supply channel 8B that openslaterally into the valve accommodating bore 2B extends from the bottomhousing plane of reference E1 to the top housing plane of reference E2and from there crosses the valve accommodating bore 2F housing theseparating valve in the direction of the wheel brake connection R2.

[0015] For the previously described course of the pressure channelbetween the braking pressure generator port B2 and e.g. the wheel brakeconnection R2, subsequently, the pressure fluid conduits will beexplained for the operation of the hydraulic unit in the pressuremaintaining phase and the pressure reduction phase exclusively for thepressure fluid supply of the wheel brake at the wheel brake connectionR2.

[0016] In the pressure maintaining phase the inlet valve in the valveaccommodating bore 2D switches into the closed position so that thehydraulic pressure in the second supply channel portion 9B is hinderedto propagate into the supply branch line 7 and, thus, to the wheel brakeconnection R2. Consequently, the pressure in the wheel supply channel 8Bremains constant. The pressure fluid supply via the supply branch line 7to the valve accommodating bore 2C and the wheel supply channel 8A isnot impaired by this provision.

[0017] When the objective is to reduce the pressure that prevails at thewheel brake connection R2, the outlet valve arranged in the valveaccommodating bore B2 will switch into the open position, with theresult that the pressure fluid that prevails in the wheel supply channel8B propagates into the return channel 11 that is connected at the bottom3 of the valve accommodating bore 2B and provides a communicationbetween the two valve accommodating bores 2A, 2B of the second valve rowY. From there the return channel 11 extends as a transverse channel toan accumulator accommodating bore 1 that is located downstream of thepump accommodating bore 5 and houses a low-pressure accumulator piston.A transverse channel 12 extends from the accumulator bore 1 and iscontinued in the space between the supply branch line 7 and the pumpaccommodating bore 5, opening into a pump pulsation damper integrated inthe pump accommodating bore 5 in the present example. When the need fora pump pulsation damper is obviated, the supply branch line 7 extendsdirectly into the pump accommodating bore 5. From the pump accommodatingbore 5 the pressure fluid delivered by the pump is conducted to thenoise damping chamber 10A via a pump pressure channel 13 that crossesthe supply branch line 7. The noise damping chamber 10A with its chamberbottom is additionally connected to the second supply channel portion 9Bso that—in dependence on the valve switch position of the inlet valveinserted into the valve accommodating bore 2D—the pressure fluiddischarged from the wheel brake R2 into the accumulator accommodatingbore 1 is supplied to the wheel brake connection 2 again, if sorequired, and the pressure that prevails at the inlet valve willpropagate via the second supply channel portion 9B, the open separatingvalve in the valve accommodating bore 2F, and the pressure supplychannel 9 into the braking pressure generator port B2.

[0018] The perspective view of FIG. 2 shows the features beingparticularly significant for the idea of the invention and necessary toensure a design of the accommodating member 4 that is optimized in termsof venting, filling and aspiration, without requiring modification ofthe pattern of connections known from the state of art in DE 198 05 843A1 for the components of the brake system (e.g. motor, control unit,brake line) that are to be attached to the housing surfaces of theaccommodating member 4. The following description of the detailsaccording to FIG. 2 thus represents a partial view of the hydraulic unitdisclosed in FIG. 1.

[0019] In detail, FIG. 2 shows the block-shaped accommodating member 4,the third valve row Z including the valve accommodating bores 2E, 2F aswell as the pump and motor accommodating bores 5, 14 and the noisedamping chamber 10A, 10B for the hydraulic unit of the type describedhereinabove. On the housing surface A2 remote from the noise dampingchambers 10A, 10B, there are the two above-mentioned braking pressuregenerator ports B1, B2 for the brake line screw coupling to adual-circuit master brake cylinder whose brake fluid is supplied fordriving dynamics control to a pump arranged in the pump accommodatingbore 5 by way of the suction channel 6 drafted exemplarily for a brakecircuit portion. To this end, pressure fluid is conducted through ashort channel portion of the braking pressure generator port B2vertically into the valve accommodating bore 2E that houses the electricchange-over valve. In a driving dynamics control operation, the electricchange-over valve adopts its open position so that the pressure fluid isdirected from the horizontal line into the vertical line correspondingto the arrow shown within the valve accommodating bore 2E. The result isthat the pressure fluid is conducted in the direction of the suctionchannel 6 arranged at the bottom 3 of the valve accommodating bore 2E,said channel crossing as a transverse bore the valve accommodating bore2E from the direction of the second housing surface A2. The opening ofthe transverse bore disposed at the second housing surface A2 is closedby a plug or a ball so as to be pressure-fluid tight. The ball ispress-fitted into the suction channel 6 as close as possible towards thevalve accommodating bore 2E in order to minimize the clearance volume ofthe suction channel 6. The end of the suction channel 6 that is remotefrom the valve accommodating bore 2E opens into the pump accommodatingbore 5.

[0020] An especially short, low-resistance suction conduit between thebraking pressure generator port B2 and the pump accommodating bore 5 isfavorably achieved due to the chosen position of the valve accommodatingbore 2E. Thus, the suction channel 6 is easy to vent and to replenish.In addition, this arrangement permits aspirating the pressure fluid byway of the braking pressure generator port B2 on the shortest way fromthe pump in the pump accommodating bore 5 in a quick and reliablefashion. Corresponding to FIG. 2, the pump accommodating bore 5 on thesuction side includes a pulsation-damping chamber and on the pumppressure side an additional noise-damping chamber 15 that is designed asan annular chamber and is integrated as a stepped bore in the pumpaccommodating bore 5. The pump pressure channel 13 is provided for thepressure-side connection of the pump accommodating bore 5 to thenoise-damping chamber 10A, said pump pressure channel being directedequally as a transverse bore into the bottom of the cylinder-shapednoise damping chamber 10A which, inserted from outside into theaccommodating member 4, is closed by a cover. The second supply channelportion 9B that is known from FIG. 1 already crosses the pumpaccommodating bore 5 in the direction of the valve accommodating bore 2Faccommodating the electric separating valve, so that the pressure fluidsupplied from the pump bore 5 to the noise damping chamber 10A willescape in the noise damping chamber 10A in the direction of the secondsupply channel portion 9B and propagate up to the electromagneticallyclosed separating valve by way of the second supply channel portion 9Bthat opens into the bottom 3 of the valve accommodating bore 2F.

[0021] Different from FIG. 2, FIG. 3 shows an alternative of thearrangement of the suction conduit between the braking pressuregenerator port B2 and the pump accommodating bore 5 in the accommodatingmember 4. In this alternative, the braking pressure generator port B2 isdisposed at the level of the transverse bore that penetrates the bottom3 of the valve accommodating bore 2E, a closure member 16 configured asa ball being inserted into said transverse bore, with the result thatthe portion of the suction channel 6 that extends linearly in thetransverse bore is subdivided into two portions 6A, 6D. Consequently, indirect adjacency to the braking pressure generator port B2 at the levelof the housing plane E1 is the horizontally extending first portion 6Aof the suction channel 6, following which is a second portion 6Bpointing in a vertically downward direction towards the housing surfaceA1, said portion 6B being connected to a third portion 6C of the suctionchannel 6 that opens in a radial direction into the valve accommodatingbore 2E of the electric change-over valve at the level of the housingplane E1. In the open position of the electric change-over valve, thereis thus a pressure fluid connection by way of the valve accommodatingbore 2E to the fourth portion 6D of the suction channel 6 that extendsfrom the bottom 3 of the valve accommodating bore 2E to the pumpaccommodating bore 5. The description of FIGS. 1 and 2 is referred toregarding the further pressure fluid conduits that can be seen in thedrawing of FIG. 3. It becomes apparent from FIG. 3 that the closuremember 16 is inserted into the portion of the transverse bore, which isinterposed between the second portion 6B of the suction channel 6 andthe valve accommodating bore 2E.

[0022] In another embodiment of the subject matter of the inventionaccording to FIG. 4, the valve accommodating bore 2E provided for theelectric change-over valve is penetrated by fluid in oppositedirection—what is in contrast to the illustrations in FIGS. 1, 2, and3—so that the braking pressure generator port B2 opens into the bottom 3of the valve accommodating bore 2E, and from there fluid flow takesplace through the valve accommodating bore 2E in a vertically downwarddirection towards the housing plane E1, with the electric change-overvalve open. In this bottom area of the valve accommodating bore 2E, atransverse bore having the function of the suction channel 6 from thedirection of the housing surface A2 is tangent to the valveaccommodating bore 2E in the direction of the pump accommodating bore 5,with the result that there is a short suction conduit for the pumpbetween the valve accommodating bore 2E and the pump accommodating bore5 succeeding which is the pump pressure channel 13 similar to FIGS. 1 to3.

[0023] Thus, the channel arrangement (arrangement of bores in the block)in the accommodating member 4 presented by way of FIGS. 1 to 4 achievesa particularly simple, functionally improved hydraulic unit whichprovides optimal conditions in terms of ventilation ability, fillingwith brake fluid, and pressure fluid supply for the pump, without theneed for modifications to the pattern of connections for the valves, themotor, and for the pressure fluid connections at the accommodatingmember 4 as known from the prior art in DE 198 05 843 A1. A shortestpossible suction channel 6 is achieved by arranging the third valve rowZ between the braking pressure generator ports B1, B2 and the pumpaccommodating bore 5.

[0024] List of Reference Numerals:

[0025]1 accumulator accommodating bore

[0026]2A valve accommodating bore

[0027]2B valve accommodating bore

[0028]2C valve accommodating bore

[0029]2D valve accommodating bore

[0030]2E valve accommodating bore

[0031]2F valve accommodating bore

[0032]3 bottom

[0033]4 accommodating member

[0034]5 pump accommodating bore

[0035]6 suction channel

[0036]6A portion of the suction channel

[0037]6B portion of the suction channel

[0038]6C portion of the suction channel

[0039]6D portion of the suction channel

[0040]7 supply branch line

[0041]8A wheel supply channel

[0042]8B wheel supply channel

[0043]9A first supply channel portion

[0044]9B second supply channel portion

[0045]10A noise damping chamber

[0046]10B noise damping chamber

[0047]11 return channel

[0048]12 transverse channel

[0049]13 pump pressure channel

[0050]14 motor accommodating bore

[0051]15 noise damping chamber

[0052]16 closure member

[0053] B1 braking pressure generator port

[0054] B2 braking pressure generator port

[0055] R1 wheel brake connections

[0056] R2 wheel brake connections

[0057] E1 bottom housing plane of reference

[0058] E2 top housing plane of reference

1. Hydraulic unit for slip-controlled braking systems including anaccommodating member accommodating inlet and outlet valves in severalvalve accommodating bores of a first and a second valve row, said valvesopening into a first housing surface of the accommodating member that isdisposed at right angles to a second housing surface into which severalbraking pressure generator ports open, with a pump accommodating borearranged in the accommodating member and being directed transversely tothe direction the valve accommodating bores open into the accommodatingmember, wherein the valve accommodating bores for the outlet valves arearranged in the second valve row that is in direct adjacency to the pumpaccommodating bore, with a motor accommodating bore arranged in theaccommodating member and being directed vertically to the pumpaccommodating bore, with an accumulator accommodating bore opening intothe accommodating member, with several pressure fluid channels thatconnect the accommodating bores for valve, pump and accumulator andenable a hydraulic communication between a braking pressure generatorand several wheel brakes, characterized in that the inlet valves arearranged in the valve accommodating bores (2C, 2D) of the first valverow (X) which is spatially separated from the second valve row (Y)accommodating the outlet valves by means the pump accommodating bore(5), in that several valve accommodating bores (2E, 2F) of a third valverow (Z) remote from the pump accommodating bore (5) open directlybetween the second valve row (Y) and the braking pressure generatorports (B1, B2) into the first housing surface (A1) of the accommodatingmember (4), and in that for the hydraulic communication between at leastone braking pressure generator port (B1 or B2) and a suction-sideconnection of the pump accommodating bore (2) there is provision of anelectric change-over valve closed in its basic position in at least onevalve accommodating bore (2E) of the third valve row (Z), the hydrauliccommunication between said change-over valve and the pump accommodatingbore (5) being established by way of a portion of a suction channel (6),the length thereof being determined by the distance between the pumpaccommodating bore (5) and the third valve row (Z).
 2. Hydraulic unit asclaimed in claim 1, characterized in that a pressure-side outlet of thepump accommodating bore (5) opens into a noise damping chamber (10) thatis arranged adjacent to the first valve row (X) in the accommodatingmember (4) remote from the second and third valve row (Y, Z). 3.Hydraulic unit as claimed in claim 1, characterized in that the valveaccommodating bore (2E) of the third valve row (Z) accommodating theelectric change-over valve is designed as a blind-end bore which extendsfrom the direction of the first housing surface (A1) up to the bottom(3) of the blind-end bore, which is crossed by the suction channel (6)and is tangent thereto in the area of bottom (3), and in that one of thebraking pressure generator ports (B1 or B2) opens at a vertical distancefrom the bottom (3) into the valve accommodating bore (2E) of the thirdvalve row (Z) in such a manner that depending on the valve switchposition of the electric change-over valve associated with the valveaccommodating bore (2), there is a direct pressure fluid connection ofthe suction channel (6) between the braking pressure generator port (B1or B2) and the pump accommodating bore (5) by way of the valveaccommodating bore (2E).
 4. Hydraulic unit as claimed in claim 1,characterized in that the valve accommodating bore (2E) provided for theelectric change-over valve is configured as a blind-end bore thatextends from the direction of the first housing surface (A1) to thebottom (3) of the blind-end bore, and in that in the area of the bottom(3) the suction channel (6) is continued linearly until the brakingpressure generator port (B1 or B2).
 5. Hydraulic unit as claimed inclaim 4, characterized in that a first and a fourth portion (6A, 6D) ofthe suction channel (6) is produced by a drilling operation directedinto the second housing surface (A2), said portion extending up to thepump accommodating bore (5), in that a second portion of the suctionchannel (6B) is produced by another drilling operation that is directedinto a third housing surface (A3) disposed opposite the first housingsurface (A1), said second portion opening into the first portion ofsuction channel (6A) produced by the first drilling operation, and inthat the second channel portion (6B) of the suction channel (6) isinterposed directly between the valve accommodating bore (2E) of theelectric change-over valve and the braking pressure generator port (B1,B2).
 6. Hydraulic unit as claimed in claim 5, characterized in that athird channel portion (6C) that opens from the direction of the secondhousing surface (A2) into the valve accommodating bore (2E) of theelectric change-over valve in parallel to the braking pressure generatorport (B1 or B2) is introduced into the valve accommodating bore (2E) ofthe electric change-over valve, said third channel portion (6C)extending from there to the pump accommodating bore (5) by way of afourth channel portion (6D) that is continued coaxially to the firstportion (6A) of the first suction channel (6).
 7. Hydraulic unit asclaimed in any one of the preceding claims, characterized in that aclosure member (16) is mounted into the housing channel opening as atransverse bore from the direction of the second housing surface (A2) inorder to prevent a short-circuit current between the first and thefourth portion (6A, 6D) of the suction channel (6).
 8. Hydraulic unit asclaimed in claim 7, characterized in that the closure member (16) ispositioned in the portion of the transverse bore disposed between thevalve accommodating bore (2E) and the second channel portion (6B) of thesuction channel.
 9. Hydraulic unit as claimed in claim 8, characterizedin that the closure member (16) is designed as a ball that ispress-fitted into the channel bore from the direction of the brakingpressure generator port (B1 or B2).